The present invention relates to a semiconductor device, particularly to a parallel plate diode.
The conventional semiconductor diodes has an p-n junction structure made of semiconductor materials in which the carriers make orientated movements when extra electric field force is applied and they exhibit unidirectional conductivity. Such semiconductor diodes are mainly used as rectifying or switching device. Evidently, when no bias voltage or bias current is applied, the unidirectional conductivity of such diodes will disappear and become ordinary linear devices. There is another semiconductor device called selenium pile, made of several plate-like semiconductor materials, e.g., selenium rectifying plates, in series connection. It is a rectifying device that exhibits unidirectional conductivity only when extra electric field exists.
An object of the present invention is to provide a parallel plate diode that can maintain unidirectional conductivity in the circuit with no application of bias voltage or bias current.
In order to accomplish the object mentioned above, a parallel plate diode comprising metal electrodes and semiconductor materials contacting metal electrodes, wherein the two thin plate electrodes made of metal are disposed in parallel, and a layer of thin plate semiconductor material sandwiched between the two thin plate electrodes. The concentration of the carriers in the semiconductor material layer is 20% or less than that of the electrons in the metal. One of the metal electrodes is made so as to have a plurality of recesses from its surface into the interior on the side that faces the semiconductor coat layer. The diameter of those recesses is less than 4 micrometers.
Preferably, said recesses are well-shape cavities.
The parallel plate diode according to the present invention can be used as the detecting diode, which can improve the performance of the radiodetector. Furthermore, it can also be used as an electronic watch, a micro calculator as well as the power of other small power electric appliances.